<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>CSS 语法</title>
  <style>
    p {
      color: red;
      text-align: center;
    }
  </style>
</head>
<body>

<p>Hello World！</p>
<p>这些段落是通过 CSS 设置样式的。</p>

</body>
</html>